Band brake



45 i ythrough a slot Patented Sept. 1, 1925.

UNITED'STATES PATENT oF EDGAR JOSEPH DE NORMANVILLE, or LONDON, ENGLANn.

FICE. I

BAND BRAKE.

Application leq'August 28, 1922. Serial No.`584,790.

' and to move the other end by means of a .inventionf j y 5F1gure 2 1s asimilar View of a modified mounting. e 35 "y operating lever hereinafter referred to'. V

spring or other` connection. This arrangement operates satisfactorily ,so long as the drum has 1a tendency or is able 'to rotate in only Aone direction but is inellicient when the direction in which the drum' has a tendency torotate is reversed. 1 Y

This invention provides a brakeI .band mounted and operated Vso that it acts efficiently on the drum when the latter rotates or tends to rotate in eith'erpdirection. y

The' accompanying drawing shows how the said invention may be conveniently andl advantageously carried into practice. f

In this drawing z-p Y Figure 1 is a'n end View, with parts in section, of Va brake drum provided with a brake band mounted in accordance with this constructional form of `the .brake `band Figure 3 isfa detail Iviewtof a earn bar Referring to Figure 1, 5 is a brake'drum around which* is lapped a vbrake band 6 the ends of which are respectively secured to .brake blocks 7, 7. These brake blocks may 'be arranged'- to make contact lindrical lsurface of .the drum,

with the cyor as shown they may engage in agroove 8, or `grooves in the .periphery ofthe drum. Each brake block is carried by-apin or bar 9 passing in vthe block and extending between the -limbsof the forkedend of a corresponding lever 11 which can rock on a'pivot pin 12 carriedby a Vfixed frame part.

The levers 11'v are moved about the. pivot pins 12 by engagement `with spring pressed plungers 13 arranged in alignment in guideways 13*v having closedends and movablel towards. each otherv byv springs 14. The

.plungers 13 can be movedapart-by wedge or cam surfaces: 15 provided on opposite `a convenient .enclosingthe drum, acts as` a fixed anchor sides of a( longitudinally slidable bar 16, seen in transverse section plungers.

With this construction, when the bar 16 is in a position-in which the cams 15 thereonare located between the plungers 13 to holdthe same separated, with the springs 14: under compression, the levers 11 are .in Figure 1, ar-k ranged between the *proximatev ends of themoved'to the positions indicated in 'broken lines, thereby carrying theblocks 7 -out of Contact with the brake drum and alsoslackening the `band 6 so that the drum v5 can revolve freely so far as the 'action of the brake is concerned. f

v If now the bar 16 is moved so that the `cams 'are carried away" from between the plungers, then the llatter yare movedby 4,their springs and bring the levers 11 to the positions iii-which they are shown in full lines,

whereby also the blocks 7 are brought into contact with the drum. Assumingthe drum to be revolved .in counter-clockwise direction, as vindicated by the arro\w,the block at the right handside' of Figure 1 will, by its frictional engagement with Vthe "drum, be

moved from the position indicated in Ibroken lines tol that indicated 'in fullI lines thereby tightening vthe brake-band 6. The brake block ,at the left hand side Vof Figure 1 resting against a stop or abutment17 on partof the frame creasing agefor the `end ofthe brake ybandattached thereto.

By attaching to `biakeblocks so as to be,A moved thereby, a construction is provided inwhich the brake band is self adjusting, for example, to take up wear eitherof the brake band or of the drum, or to allow for expansionin the event of the drum or vthenband becoming overheated. Moreover, Awhenl the band vis released from the drum, the weight of the blocks thus left free to Vdrop within the casthe. endsn of the brake band ing, yoperates toeXpand the band and lhold it? 1n Contact with the casing so that'it kdoes not chatter or rattle. f f

In the Yevent of the drum commencin to rotate in the clockwise direction the b ook Von the. right hand side is carried with the drum into contactwithitsabutment 17 and becomes afxed anchorage for the end of the band attached thereto. .At the Sametime -theQbrake band is` closelyapplied to the drum'by P1111 *.O the block on 'the left 60k plunger spring which opposes this moveferent velocity ratios, tvvo or morefvvedge or cam bars 16 are provided and, preferably, veach bar is moved singly, in turn, by a single operating lever or handle. A suitable arrangement, shown in Figure 3, comprises a lever 18 having a rocking movement about a pivot pin 19 mounted in a ball or cylinder 2O mounted to turn in bearings in a direction at right angles to the movement of the lever 18 about the pivot 19. Sliders .21 respectively connected to the bars 16 can be engaged singly by the lever 18 by rocking the cylinder 20, and then the lever can be rocked on the pivot 19 to move the selected slider longitudinally. In addition the lever may be mounted to have a vertical movement on the pivot pin 19 so that it can be brought into engagement With other sliders or Wedge carrying bars either by a vertical movement alone or by combined vertical and lateral rocking movements.

In the modified' constructional .arrangement shown in Figure 2, the plungers 22 a-re arranged to move on paths which intersect at right angles and the ends of the plungers have iats 23, 24: formed thereon the surfaces of Which are likewise disposed at right Yangles and are inclined symmetrically on opposite sides ofv the axis of the path on which the plunger moves. In this arrangement the brake blocks are .omitted rand opposite ends of the brake band 25 are respectively connected directly to the plungers. Wedge or cam surfaces 26 are lprovided on a bar 27 to act on the flats 23 on theA plungers and push them downwardly into their guidevvays against the thrust of the springs 28, to the position in Which the plunger on the left hand side of Figure 2 is shown. Then both` plungers are in this position the brake band is slackened releasing the drum.

Then the Wedges or cams are moved out ofthe path of the plungers the latter are moved by their springs thereby tightening the brake band onto the drum. Then if the drum commences to rotate in either direction the vband moves with the drum, the

ment, is compressedvvhilst the other spring advances its; plunger to maintain the brakev band in effective contact. With the drum.

Assuming the drum to` rotate in the direc tionindicatedE byv thearrow, the spngngr 28 The bar 27 may have other Wedges or cams thereon to associate the operation of s the drum 5 with other drums comprised, for Y example in the same variable velocity ratio gearing. A bar 29 is provided to act Von the iats 24 by means of Wedges or cams 30 in a manner similar to that in Which the bar 27 acts on the flats 23. These bars can conveniently be operated by a lever such as that shown in Figure 3. Other Wedge or cam bars may alsobe provided, for example, a bar 31 operated by the `same lever as that operating the bars 27, 29, or independently,

as for example by a pedal, the Wedges or cams 32 on this bar being arranged to'v put out of operation, simultaneously, all fthe bra-ke bands controlled by cams orvvedges on the bars 27, 29 independently of the position of'these bars. What I claim is Y I 1. A brakeinechanism for brakinga rotary drum, comprising a brake band, plungers respectively connected to opposite ends of the band, springs respectively acting on the said plungers, fixed :tramel parts providing bearings for .the said springs, and means for moving and holding the said plungers against the action of their springs.

2. A brake mechanism for braking a rotary drum, comprising a brake band,inde

-pendently movable plungers respectively` connected to opposite ends v'of the band, springs respectively acting separatelyA on the said plungers, and means forv moving and holdingfsaid plungers against' the action of their springs.` f f 3. A brake mechanism or'braking` a rotary drum, comprising a brake band, spring n pressed plungers operatively connected to opposite ends of the band respectively, and

guideways for receiving and limiting the movement of each plunger.

4. A brake mechanism for braking a rotary drum, comprising afbrake band, plungers operatively connected toopposite ends vof the band respectively, guidevvays having closed ends for receiving and limiting the movement of'each plunger in one direction and springs for moving each plunger away fromfthe closed` end of its guidevvay.

5.. A brake mechanism for braking. a rotary drum, comprising a brake band, plungers operatively connected vto opposite ends of the band' respectively, Vgindevv-ays With closedl ends for receiving and limiting the Vers movable in oppositely arranged guide-- ways and operatively connected to opposite ends of the band respectively, and springs for moving the plungers towards each other in the said guideways.

7. A brake mechanism for braking a rotary drum, comprising a brake band, brake blocks respectively connected to opposite ends of the band, spring pressed plungers movable in guideways and levers for communicating motion from the said plungers to the brake blocks.y

8. A brake mechanism for braking a rotary drum, comprising a brake band, brake blocks respectively connected to opposite ends of the band, spring pressed plungers movable in guideways, levers for communieating motion from the said plungers to the brake blocks, between each lever and the corresponding brake block.

9. A brake mechanism for braking a rotary drum, comprising a brake band, brake blocks respectively connected to opposite ends of the band, Vspring pressed plungers movable in guideways, levers pivotally and a pin and slot connection mounted on a fixed frame part and movable by means of the said plungers, a pin and slot connection between each lever and thel Y corresponding brake block, and stops on the Xed frame part for limiting the movement of each of the brake blocks.

l0. A brake mechanism for braking a rotary drum, comprising a brake band, brake blocks respectively connected to opposite ends of the band, spring pressed plungers movable in guideways, levers operated by the plungers when free to move under the action of their springs to apply the brake blocks to thedrum, and a pin and slot con-` nection between each brake blockvand the corresponding lever.

l1. A brake mechanism for braking a rotary drum, comprising a brake band, brake blocks respectively secured to the ends of said band, levers for moving the brake blocks into contact with the said rotary drum, a pin and slot connection between each brake block and its lever allowing a restricted movement of the brake blocks with the drum when pressed against the latter, stops provided on a fixed frame part to limit such movement of the brake blocks, spring pressed plungers operating to move the said levers kto apply the brake fblocks to the drum, and means for moving and holding the said plungers against the action of their springs.` v

EDGAR JOSEPH DE N ORMANYILLE. 

